Combination ammonium sulfate/drift reducing adjuvant and wet bond process for making the same

ABSTRACT

The present invention is directed to a combination adjuvant comprising an ammonium sulfate fertilizer impregnated with a drift reducing agent. The drift reducing agent is preferably polyacrylamide. Anti-caking and drying agents are preferably added to the combination adjuvant to provide ease of use and prevent caking and agglomeration of the adjuvant. The combination adjuvant is formed by mixing a liquid drift reducing agent with dry ammonium sulfate granules. Any additional agents are added and mixed with the drift reducing agent and ammonium sulfate. Because each granule comprises approximately the same amount of drift reducing agent, the composition of the combination adjuvant is uniform, even after storage and transport.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to the field of spray adjuvants. Morespecifically, the present invention is directed to a spray adjuvantcomprising both a fertilizer and drift reducing agent.

2. Description of Related Art

Agrochemicals, such as herbicides, insecticides, fungicides and othercrop protection chemicals frequently require the presence of adjuvantsto achieve maximum, or even acceptable, performance. The term “adjuvant”includes any ingredient added to an agrochemical to aid or modify theaction of the agrochemical, or to alter the physical characteristics ofan agrochemical spray composition, including, but not limited to,formulation aids. Generally, the agrochemical, adjuvants and water aremixed in a tank to form an agrochemical spray composition, which issprayed onto a target area, such as a field.

There are many types of adjuvants. Drift reducing agents are adjuvantsthat modify the drift and deposition characteristics of the agrochemicalspray composition. Drift, a longtime problem with agrochemical spraycompositions, is a function of water droplet size. As a result of drift,the agrochemical spray composition is carried away from its intendedtarget, resulting in wasted product, unintended treatment of bordercrops that may be damaged by the composition and potential air, groundand water pollution. It is generally agreed that droplets with diametersof 100 microns or less are most susceptible to drifting off target.Droplets with diameters over 100 microns are more likely to produce evenspray patterns that uniformly cover the target area, with little drift.Most drift reducing agents generally increase the viscosity of theagrochemical spray composition, which increases droplet size, decreasesdrift and increases deposition of the agrochemical spray composition onthe target. However, if the viscosity is too high, the agrochemicalspray composition will not be applied evenly. Rather, the spray patternwill comprise streaks of heavy and light application within the targetarea, which can damage the over-sprayed plants and reduce insect or weedcontrol in the under-sprayed areas.

Known drift reducing agents include natural gums, such as guar gum andits derivatives, and synthetic polymers, such as polyacrylamide,polyethylene oxide and polyvinylpyrrolidones. Synthetic polymers may besupplied to the end user in an organic carrier solvent for addition tothe agrochemical spray composition in the tank. Use of the organicsolvent can limit the dispersibility of the polymer and requires the enduser to deal with the potential problems associated with a volatileorganic compound. Other synthetic polymers are provided in a dryflowable form. The dry flowable polymers must swell upon mixing in thetank to increase the viscosity of the agrochemical spray composition.Such dry flowable polymers often cause nozzle and/or filter cloggingduring application and are generally recognized to produce an adversespray pattern uniformity that increases the likelihood of inconsistentpesticide coverage.

Other types of adjuvants are anti-foam and de-foaming agents. In manyagrochemical spray composition, substantial foaming occurs in the spraytank during mixing and application of the composition. For example, theherbicide glyphosate, sold under the trademark “ROUNDUP ULTRA,” includessurfactants that create foam in the tank mix. It is desirable to includean adjuvant to help prevent the foam from forming or to knock downexisting foam. Antifoam agents are adjuvants designed to be added to thetank mix to prevent foam in the spray tank, whereas de-foaming agentsare adjuvants designed to knockdown foam once it has developed in thespray tank. Some antifoam agents provide knockdown ability and can beused for both purposes. When used herein, the term “antifoam agents”generally refers to agents that prevent and/or knockdown foam.

Yet another category of adjuvants are activator adjuvants, which enhancethe biological performance of the agrochemical spray composition.Activation adjuvants include water-soluble nitrogen-based fertilizers,such as ammonium sulfate. Ammonium-containing fertilizers reduce the pHof the agrochemical spray composition, improving uptake on certain weedspecies.

Ammonium-containing fertilizers, in particular ammonium sulfates, areparticularly useful in enhancing herbicide efficacy. The sulfate portionreleased by ammonium sulfate “conditions” the water of the agrochemicalspray composition by binding hard water minerals such as calcium,sodium, iron and magnesium and thereby preventing such minerals fromantagonizing the herbicide. This is particularly true when used withglyphosate herbicides or other weak acid herbicides. It is believed thatthe ammonium ion enhances glyphosate performance by binding with theglyphosate to form a more soluble, readily absorbed glyphosate-ammoniumcomplexes. Glyphosate-sodium and glyphosate-calcium complexes are lesssoluble and therefore not as readily absorbed. The sulfate ions releasedby the ammonium sulfate precipitate the sodium and other hard waterminerals, leaving the glyphosate molecules free to bond with theammonium ions. Larger amounts of ammonium sulfate are required whenharder water sources are used in the agrochemical spray composition ofcertain herbicides. Additionally, ammonium-containing fertilizersincrease the absorption of agrochemicals into target plants bystimulating growth of the plant, and aiding uptake into the phloem sothat the agrochemicals can be translocated.

Fertilizer grade ammonium sulfate is generally comprised of largeparticles that are difficult to dissolve in agrochemical spraycompositions and may contain insoluble impurities that can damage sprayequipment and clog spray nozzles. As a result, ammonium sulfate is oftenprocessed before it can be used as an adjuvant in agrochemical spraycompositions. Dry ammonium sulfate can be screened to a smaller particlesize that will disperse more quickly when mixed in the spray tank.During the screening and handling process, the material is screened forimpurities. Alternatively, the ammonium sulfate may be pre-solubilizedin water and packaged into liquid containers, during which process it isfiltered to remove impurities. However, because the holding capacity ofwater is limited, in order to achieve the high rates of ammonium sulfateoften needed, an unacceptably large amount of product is required, andend-users must dispose of the bulky liquid containers.

If end-users wish to use multiple adjuvants, they are required tomeasure the appropriate amounts of the individual adjuvants,agrochemical and water, and mix the components in the tank to form theagrochemical spray composition. The end-user must ensure that the amountof the components are correct, the materials are compatible and properlydispersed, and proper safety precautions are followed. Because this canbe a complicated and time consuming task, there is a need for adjuvantproducts that combine two or more adjuvants to simplify preparation ofthe agrochemical spray composition.

One known method for providing a combination adjuvant involves dryblending two types of adjuvants, such as a fertilizer and a dry driftreducing agent. However, because the fertilizer particles are generallylarger than those of the drift reducing agent, the particles separateduring shipment, such that the mixture does not have a uniformcomposition. To assure the separate components stay mixed, it is knownto grind the two materials to similar sizes, so that they will notsegregate during shipping and handling. However, grinding to a smallparticle size results in a fine-dusty end product that is difficult forthe end-user to use. Further, finely ground dry drift reducing agentstake considerable time to hydrate and achieve the desired viscosity.When the drift reducing agent does not hydrate quickly enough, it canagglomerate and plug screens and nozzles during application.

Ammonium sulfate is commonly used as an activator adjuvant to enhancethe performance of herbicides, particularly glyphosate. Commercialbrands of glyphosate, such as that sold under the name “ROUNDUP,”recommend varying rates at which the ammonium sulfate should be used inassociation with the product, referred to as “use rates.” Thus, it isdesirable for any combined fertilizer and drift reducing product to beuseful over the entire range of the recommended ammonium sulfate userates. However, as more ammonium sulfate is added to the agrochemicalspray composition, more drift reducing agent is added. As a result, whenlarge amounts of fertilizer are added, too much drift reducing agent isadded, resulting in a composition with a viscosity that is too high forproper application. If the amount of drift reducing agent in the blendis reduced, it will not provide sufficient drift reduction at low userates. Thus, when the drift reducing agent is dry blended with thefertilizer, the range of use rates for the blended product is limited.

Thus, a need remains for a single product that supplies two or moretypes of adjuvants, and can be used over a wide range of use rates,without the problems associated with dry blended adjuvant mixtures.

SUMMARY OF THE INVENTION

The present invention is directed to a combination adjuvant comprising afertilizer and a drift reducing agent, wherein the fertilizer granulesare impregnated with the drift reducing agent. In a most preferredembodiment, the combination adjuvant also comprises a drying agent andan anti-caking agent. The combination adjuvant may additionally comprisean anti-foam agent.

The combination adjuvant is formed by a wet bond process, wherein thefertilizer is uniformly mixed with a liquid drift reducing agent. Inthis wet bonding process, the liquid drift reducing agent is able topenetrate the fertilizer granules, and thereby impregnates the outerportion of the granules with the drift reducing agent. However, it ispossible that the drift reducing agent simply binds to the exterior ofthe fertilizer granules. For the sake of clarity, when used herein,“impregnated” fertilizer granules refers to fertilizer granules to whicha liquid drift reducing agent has been applied, regardless of whetherthe drift reducing agent actually penetrates, or is simply bound to, thefertilizer granules. In addition, “granules” refer to the particles thatmake up the fertilizer, regardless of shape or size.

In the wet bond process of the present invention, the fertilizer andliquid drift reducing agent are preferably mixed until thoroughlyblended for at least approximately three minutes. If additionaladjuvants and/or formulation aids are desired, they are added to thecombined fertilizer and drift reducing agent and mixed further. Theadditional adjuvants may be in dry form, which are dry blended with thepolyacrylamide-impregnated ammonium sulfate particles and/or bonded tothe ammonium sulfate granules via the liquid polyacrylamide.Alternatively, the additional adjuvants may be in liquid form, which canpenetrate and impregnate the ammonium sulfate granules.

In a preferred embodiment, the fertilizer is ammonium sulfate. Becauseammonium sulfate has very little absorbency, only a small amount of theliquid drift reducing agent can be absorbed by the ammonium sulfategranules. Therefore, the drift reducing agent must be effective in smallamounts. In addition, insofar as many ammonium sulfate applicationsrequire wide ranges of ammonium sulfate content, the drift reducingagent impregnated within the ammonium sulfate must also be effectiveover a wide range of use rates, and must be present in the combinationadjuvant in an amount that will be effective throughout the use rangefor the ammonium sulfate. Preferred drift reducing agents to achievethese characteristics are synthetic polymers, more preferably syntheticpolymers selected from the group consisting of anionic polyacrylamides;non-ionic polyacrylamides; cationic polyacrylamides; polymers of acrylicacid; copolymers of acrylic acid; methacrylic acids and their salts;methylacrylamides and their copolymers, derivatives and mixturesthereof; polyacrylonitrile, its hydrolysis products, and copolymers,derivatives and mixtures thereof; polymers of ethylene oxides; andpolymers of alkylene oxides. Anionic polyacrylamide is the mostpreferred drift reducing agent. To achieve the preferred amount of driftreducing agent in the combination adjuvant, an undiluted drift reducingagent preferably comprises between 0.01 and 25 weight percent, morepreferably between 0.01 and 5 weight percent, of the total weight of thecomponents blended to form the combination adjuvant.

In a preferred embodiment, the combination adjuvant further comprises adrying agent and/or anti-caking agent. Ammonium sulfate impregnated witha drift reducing agent will provide drift reduction and enhance theperformance of the agrochemical spray composition. However, due to thecharacteristics of the ammonium sulfate and the addition of the liquiddrift reducing agent, the ammonium sulfate granules can become tackyand/or cake, preventing easy flow and complete dissolution of thecombination adjuvant and causing the combination adjuvant to agglomerateand clog spray nozzles during application. Therefore, to improve theease of use and dissolution, and to prevent nozzle clogging, use of adrying agent and an anti-caking agent is preferred. Furthermore,although use of drying and anti-caking agents is known in the art, thepresent invention comprises types and amounts of drying and anti-cakingagents that have been found to optimize the characteristics of the novelcombination adjuvant.

To reduce tackiness and enhance flow of the combination adjuvant, thecombination adjuvant of the present invention preferably comprises adrying agent selected from the group consisting of sodium sulfate,calcium bentonite, diatamaceouos silica, polyethylene glycol (flakes,prill or powder), calcium silicate, magnesium silicate, aluminumsilicate, sodium silicate, polyvinylpyrrolidone, polysaccharide, freeflowing silica, mica, cellulose powder, kraft lignin, lignosulfonates,sulfosuccinates, sodium salt of polymerized naphthalene sulfonic acid,sodium salt of carboxylated polyelectrolyte, POE stearates, dioleates,sodium butyl naphthalene sulfonates, sodium sulfonate of naphthaleneformaldehyde condensate, di-n-butyl sodium naphthalene sulfonate,di-isopropyl sodium naphthalene sulfate, sodium dodecylbenzenesulfonate, polyacrylates, polycarboxylates, solid block co-polymers, POElauryl alcohol and sorbitan stearates, preferably sodium sulfate, mostpreferably anhydrous sodium sulfate. Preferably the drying agentcomprises between 0.01 and 20 weight percent of the components blendedto form the combination adjuvant.

The most-preferred anti-caking agent for use with the present inventionis silicon dioxide. Other preferred anti-caking agents are selected fromthe group consisting of tricalcium phosphate, silicas (fumed or freeflowing), hydrophobic starch derivatives, powdered cellulose, calciumsilicate, magnesium silicate, aluminum silicate, sodium silicate,polyacrylic acid and sodium salts thereof, and sodium polyalkylnaphthalene sulfonate. Preferably the anti-caking agent comprisesbetween 0.01 and 20.0 weight percent of the components blended to formthe combination adjuvant.

An anti-foam agent may also be added to the combination adjuvant.

In the preferred embodiment, the combination adjuvant of the presentinvention is dry and free flowing and, when the preferred drying agentand anti-caking agents are added, the combination adjuvant remains freeflowing, and does not cake, during transport and storage. Thecombination adjuvant is readily dispersible in water with minimalagitation. It may be added to the spray tank with the desiredagrochemical, preferably glyphosate, and mixed to form an agrochemicalspray composition.

The combination adjuvant of the present invention has a nearly equalamount of drift reducing agent impregnated into each of the fertilizergranules, which results in uniform proportions of fertilizer and driftreducing agent throughout the combination adjuvant product. As a result,even after shipment and storage, the combination adjuvant contains theappropriate proportions of fertilizer adjuvant and drift reducing agentthroughout the product. Further, because the drift reducing agent isimpregnated within the ammonium sulfate granules, the combinationadjuvant dissolves more readily and uniformly than dry blendedcombination products.

Further, in the preferred embodiment, the combination adjuvant of thepresent invention can be used to provide a wide range of ammoniumsulfate to the agricultural spray composition, preferably including userates between 8 and 32 pounds per 100 gallons, or up to 3 pounds peracre at a 10 gallon spray carrier per acre use rate, more preferablyincluding use rates from 8.5 pounds to 18 pounds per 100 gallons, or 1-2pounds per acre at a 10 gallon spray carrier per acre use rate, withoutadversely affecting the spray pattern of the agrochemical spraycomposition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The combination adjuvant of the present invention comprises afertilizer, preferably ammonium sulfate, impregnated with a driftreducing agent, preferably a polyacrylamide. Preferably the combinationadjuvant comprises additional adjuvants and/or formulation aids selectedfrom the group consisting of a drying agent, an anti-caking agent and ananti-foam agent. More preferably the combination adjuvant of the presentinvention comprises a fertilizer impregnated with a drift reducing agentcombined with a drying agent, more preferably combined with a dryingagent and an anti-caking agent and most preferably combined with adrying agent, an anti-caking agent and an anti-foam agent.

The combination adjuvant of the present invention is formed by mixing aliquid drift reducing agent with a dry fertilizer adjuvant, such thatthe drift reducing agent is impregnated within the outer portion of thefertilizer adjuvant granules. The liquid drift reducing agent andammonium sulfate are mixed until thoroughly blended, preferably for atleast three minutes.

The preferred liquid drift reducing agent is a concentratedpolyacrylamide emulsion and the preferred fertilizer adjuvant isammonium sulfate. The polyacrylamide emulsion and ammonium sulfatepreferably are mixed in a horizontal double ribbon blender. Although adouble ribbon blender is preferred, any standard ribbon mixer, verticalmixer or Doyle type mixer with rotary flutes, or any other equipmentthat will evenly blend the dry and liquid components can be usedconsistent with the present invention. In a most preferred embodiment,spray treating equipment, including air pressurized nozzle, hose andcanister device are used to blend the liquid polyacrylamide with theammonium sulfate. Preferably the fertilizer comprises 1.0 to 99.99weight percent of the components added to the blender, more preferably92.0 to 98 weight percent, and the liquid drift reducing agent comprisesbetween 0.01 and 25 weight percent, more preferably 0.01 to 5 weightpercent.

In a preferred embodiment, additional adjuvants are mixed with thepolyacrylamide emulsion and ammonium sulfate after the ammonium sulfateis impregnated with the polyacrylamide. Preferably any desired adjuvantand/or formulation aid is added individually, and mixed until thoroughlyblended, preferably for about three minutes. In a most preferredembodiment, a drying agent, preferably sodium sulfate, is added andmixed for about three minutes, then an anti-caking agent, preferablysilicon dioxide, is added and mixed for about three minutes, followed byadding an antifoam agent and blending for about three minutes.Preferably, the drying agent, anti-caking agent and anti-foam agent areprovided in dry form. Preferably the drying agent comprises between 0.01and 20.0 weight percent of the total components added to the blender,more preferably between 0.01 and 8.0 weight percent; the anti-cakingagent comprises between 0.01 and 20.0 weight percent, more preferablybetween 0.01 and 2.0 percent, and the anti-foam agent comprises between0.01 and 5.0 weight percent of the total components added to theblender, more preferably between 0.01 and 1.5 weight percent, mostpreferably between 0.001 and 0.75 weight percent.

The resulting product is a crystalline powder, wherein each granule ofthe powder is impregnated with approximately the same amount ofpolyacrylamide, to result in a combination adjuvant with a uniformcomposition, that maintains the uniform composition during shipment andstorage.

The fertilizer of the present invention is preferably a water-solublenitrogen-based fertilizer, more preferably ammonium sulfate. Theammonium sulfate particles are sufficiently large to produce very littledust, but sufficiently small to dissolve easily in water when mixing theagrochemical spray composition. Preferably the ammonium sulfateparticles are between +14 and +120, more preferably between +16 and +65,and most preferably between +28 and +48, as determined with a W. S.Tyler Mesh Sieve by ASTM E-11 standards. Ammonium sulfate consistentwith the present invention is sold by American Plant Foods of GalenaPark, Tex. under the name “SPRAYABLE AMMONIUM SULFATE,” by MartinResources of Plainview, Tex. under the name “AMMONIUM SULFATE,” and byAllied Signal of Hopewell, Va., under the name “SULF-N 45.”

The drift reducing agent of the combination adjuvant is most preferablyanionic polyacrylamide. Other preferred drift reducing agents aresynthetic polymers, more preferably the synthetic polymer is selectedfrom the group consisting of anionic polyacrylamides; nonionicpolyacrylamide(s); cationic polyacrylamide(s); polymers of acrylic acid;copolymers of acrylic acid; methacrylic acids and their salts;methylacrylamides and their copolymers, derivatives and mixturesthereof; polyacrylonitrile, its hydrolysis products, and copolymers,derivatives and mixtures thereof; polymers of ethylene oxides; andpolymers of alkylene oxides.

The drift reducing agent is provided in a liquid form, preferably as aconcentrated emulsion. For the sake of clarity, the term “liquid,” whenused before polyacrylamide or drift reducing agent refers to anysolution of, emulsion of, or other liquid containing polyacrylamide ordrift reducing agent, respectively. Anionic polyacrylamides consistentwith the present invention are sold by Exacto, Inc. of Richmond, Ill.under the name “POLYTEX A 363” and by Nalco Chemical of Naperville, Ill.under the name “NALCO-TROL.” By adding the polyacrylamide in a liquidform, the polyacrylamide is impregnated within the outer portion of theammonium sulfate granules, which results in a combination adjuvant witha uniform composition that mixes and dissolves easily. Thus, thecombination adjuvant formed through the wet bond process overcomes thedifficulties with prior art dry blended polymers that evoke a lower, andtherefore less desirable, hydration rate, create an increased likelihoodof clogging spray nozzles and are restricted to a very narrow effectiveusage rate.

Dry ammonium sulfate has very little absorbency. Therefore, the driftreducing agent must be effective in small amounts, so that only a smallamount of liquid must be applied to and impregnated with the ammoniumsulfate. If too much liquid is added to the ammonium sulfate, theresulting material would be tacky, preventing free flow of thecombination adjuvant. The preferred drift reducing agents of the presentinvention provide the desired viscosity modification with only a smallamount of adjuvant. Preferably, the liquid drift reducing agentcomprises 0.01 to 25.0 weight percent, more preferably between 0.01 and5.0 weight percent, of the components blended to form the combinationadjuvant. Because the ammonium sulfate has little absorbency, the liquiddrift reducing agent will only penetrate the outer portion of theammonium sulfate granules and generally will not reach the center. Thus,although a uniform amount of drift reducing agent is impregnated witheach granule, the drift reducing agent is not dispersed uniformlythroughout the granules, but rather, is contained wholly, or in a higherconcentration, in the outer portion of the granules.

For the combination adjuvant of the present invention to be effectiveover a wide range of use rates, the drift reducing adjuvant must be ableto deliver the appropriate viscosity modification at a range of userates, wherein the amount of adjuvant may double from the lowest userange to the highest use range. For example, glyphosate sold under thetrademark “ROUNDUP” recommends use rates for ammonium sulfate that rangebetween 8.5 to 17 pounds per 100 gallons. Because the drift reducingadjuvant is impregnated within the ammonium sulfate, if the amount ofammonium sulfate doubles, so will the amount of drift reducing agent.The preferred polymers of the present invention supply the desiredviscosity over a wide range of use rates, such that the combinationadjuvant generally can be used to supply the full range of ammoniumsulfate use rates recommended for use with herbicides, such asglyphosate.

The combination adjuvant preferably comprises a drying agent, alsoreferred to in the art as a flow agent or moisture scavenger, whichkeeps the combination adjuvant free flowing and easy to mix. In theabsence of a drying agent, the liquid added with the drift reducingagent will cause the combination adjuvant to be tacky, such that it willnot flow freely out of the bag. Thus, the ease of use depends in part onthe amount and type of drying agent used. Addition of a drying agentalso allows the addition of more liquid drift reducing adjuvant, whilestill maintaining a dry finished product. Preferably, the drying agentcomprises between 0.01 and 20.0 weight percent of the total compounds,most preferably 0.01 and 8.0 weight percent.

The most preferred drying agent is anhydrous sodium sulfate. Sodiumsulfate acts as a moisture scavenger that reduces the hygroscopictendencies that would otherwise affect performance of the combinationadjuvant by agglomerating the combination adjuvant, impeding dissolutionof the adjuvant and clogging spray nozzles. Other preferred dryingagents are selected form the group consisting of calcium bentonite,diatamaceouos silica, polyethylene glycol (flakes, prill or powder),calcium silicate, magnesium silicate, aluminum silicate, sodiumsilicate, polyvinylpyrrolidone, polysaccharide, free flowing silica,mica, cellulose powder, kraft lignin, lignosulfonates, sulfosuccinates,sodium salt of polymerized naphthalene sulfonic acid, sodium salt ofcarboxylated polyelectrolyte, POE stearates, dioleates, sodium butylnaphthalene sulfonates, sodium sulfonate of naphthalene formaldehydecondensate, di-n-butyl sodium naphthalene sulfonate, di-isopropyl sodiumnaphthalene sulfonate, sodium dodecylbenzene sulfonate, polyacrylates,polycarboxylates, solid block co-polymers, POE lauryl alcohol andsorbitan stearates. Drying agents consistent with the present inventionare sold by Brenntag Great Lakes, LLC of Chicago, Ill. under the name“SODIUM SULFATE, STANDARD GRADE.”

The preferred embodiment of the invention additionally comprises ananti-caking agent to prevent caking and agglomeration. Ammonium sulfateby itself will tend to cake or agglomerate, which is worsened by theaddition of a liquid drift reducing adjuvant. The condition is furtherworsened as the adjuvant is stored. Thus, in a preferred embodiment ofthe invention, an anti-caking agent is added to increase the shelf lifeof the product. The most preferred anti-caking formulation aid issilicon dioxide. Other preferred anti-caking agents include tricalciumphosphate, silicas (fumed or free flowing), hydrophobic starchderivatives, powdered cellulose, calcium silicate, magnesium silicate,aluminum silicate, sodium silicate, polyacrylic acid and sodium saltsthereof, and sodium polyalkyl naphthalene sulfonate. Preferably theanti-caking adjuvant comprises between 0.01 to 20.0 weight percent ofthe components blended to form the combination adjuvant, more preferablybetween 0.01 and 2.0 weight percent. Anti-caking agents consistent withthe present invention include “HI-SIL ABS” sold by PPG Industries ofPittsburgh, Pa.

The combination adjuvant of the present invention may also contain ananti-foam agent. However, the anti-foam agent may be omitted from thecombined adjuvant, and applied to the tank mix separately, withoutadversely affecting the physical properties of the combined adjuvant. Inthe preferred embodiment, the anti-foam agent comprises between 0.01 and5.0 weight percent, more preferably between 0.01 and 1.5 weight percentand most preferably between 0.001 and 0.75 weight percent, of thecomponents blended to form the combination adjuvant. Anti-foam agentsconsistent with the present invention are sold by Magrabar ChemicalCorporation of Morton Grove, Ill., under the names “MD-1343” andMD-2454”, and by Exacto, Inc. of Richmond, Ill., under the name “SILEXDC 3018.”

The wet bond process of the present invention produces a combinationadjuvant with a uniform composition that is easy to dissolve and mix.Further, the combination adjuvant comprises a novel combination of driftreducing agent, drying agent and anti-caking agent such that in normaluse, it is free flowing, easy to use, does not cake, can be used over awide range of use rates, and retains these properties even aftertransport and storage.

From the foregoing it will be seen that this invention is one welladapted to attain all ends and objectives herein-above set forth,together with the other advantages which are obvious and which areinherent to the invention.

Since many possible embodiments may be made of the invention withoutdeparting from the scope thereof, is to be understood that all mattersherein set forth or shown in the accompanying drawings are to beinterpreted as illustrative, and not in a limiting sense.

While specific embodiments have been shown and discussed, variousmodifications may of course be made, and the invention is not limited tothe specific forms or arrangement of parts and steps described herein,except insofar as such limitations are included in the following claims.Further, it will be understood that certain features andsub-combinations are of utility and may be employed without reference toother features and sub-combinations. This is contemplated by and iswithin the scope of the claims.

1. A combination adjuvant, comprising: a plurality of water-solublenitrogen-based fertilizer granules; and a drift reducing agent; whereinsaid drift reducing agent is a liquid impregnated within the outerportion of said granules, and wherein said combination adjuvant is dryand free flowing.
 2. The combination adjuvant as claimed in claim 1,wherein said fertilizer granules are ammonium sulfate granules.
 3. Thecombination adjuvant as claimed in claim 2, wherein said drift reducingagent is selected from the group consisting of anionic polyacrylamide;non-ionic polyacrylamides; cationic polyacrylamides; polymers of acrylicacid; copolymers of acrylic acid; methacrylic acids and their salts;methylacrylamides and their copolymers, derivatives and mixturesthereof; polyacrylonitrile, its hydrolysis products, and copolymers,derivatives and mixtures thereof; polymers of ethylene oxides; andpolymers of alkylene oxides.
 4. The combination adjuvant as claimed inclaim 3, wherein said drift reducing agent is polyacrylamide.
 5. Thecombination adjuvant as claimed in claim 4, wherein said drift reducingagent is anionic polyacrylamide.
 6. The combination adjuvant as claimedin claim 3, further comprising a drying agent selected from the groupconsisting of sodium sulfate, calcium bentonite, diatamaceouos silica,polyethylene glycol flakes, polyethylene glycol, polyethylene glycolflakes, polyethylene glycol prill, polyethylene glycol powder, calciumsilicate, magnesium silicate, aluminum silicate, sodium silicate,polyvinylpyrrolidone, polysaccharide, free flowing silica, mica,cellulose powder, kraft lignin, lignosulfonates, sulfosuccinates, sodiumsalt of polymerized naphthalene sulfonic acid, sodium salt ofcarboxylated polyelectrolyte, POE stearates, dioleates, sodium butylnaphthalene sulfonates, sodium sulfonate of naphthalene formaldehydecondensate, di-n-butyl sodium naphthalene sulfonate, di-isopropyl sodiumnaphthalene sulfonate, sodium dodecylbenzene sulfonate, polyacrylates,polycarboxylates, solid block co-polymers, POE lauryl alcohol andsorbitan stearates.
 7. The combination adjuvant as claimed in claim 6,wherein said drying agent is sodium sulfate.
 8. The combination adjuvantas claimed in claim 3, further comprising an anti-caking agent selectedfrom the group consisting of silicon dioxide, tricalcium phosphate, ,silicas, fumed silicas, free flowing silicas, hydrophobic starchderivatives, powdered cellulose, calcium silicate, magnesium silicate,aluminum silicate, sodium silicate, polyacrylic acid and sodium saltsthereof, and sodium polyalkyl naphthalene sulfonate.
 9. The combinationadjuvant as claimed in claim 8, wherein said anti-caking agent issilicon dioxide.
 10. The combination adjuvant as claimed in claim 6,further comprising an anti-caking agent, selected from the groupconsisting of silicon dioxide, tricalcium phosphate, silicas, fumedsilicas, free flowing silicas, hydrophobic starch derivatives, powderedcellulose, calcium silicate, magnesium silicate, aluminum silicate,sodium silicate, polyacrylic acid and sodium salts thereof, and sodiumpolyalkyl naphthalene sulfonate.
 11. A combination adjuvant, comprising:a plurality of ammonium sulfate granules; a polyacrylamide driftreducing agent, wherein said polyacrylamide drift reducing agent is aliquid impregnated within the outer portion of said ammonium sulfategranules; sodium sulfate; and silicon dioxides, wherein said combinationadjuvant is dry and free flowing.
 12. A method for making a combinationadjuvant, comprising the steps of: providing a liquid drift reducingagent; providing dry ammonium sulfate granules; and mixing said liquiddrift reducing agent with said ammonium sulfate granules untilthoroughly mixed to form an ammonium sulfate/drift reducing agentmixture.
 13. The method as claimed in claim 12, wherein said liquiddrift reducing agent comprises between 0.01 and 5.0 weight percent ofthe ammonium sulfate/drift reducing agent mixture.
 14. The productproduced according to the method of claim
 12. 15. The method as claimedin claim 12, further comprising the steps of: adding to said ammoniumsulfate/drift reducing mixture a drying agent selected from the groupconsisting of sodium sulfate, calcium bentonite, diatamaceouos silica,polyethylene glycol, polyethylene glycol flakes, polyethylene glycolprill, polyethylene glycol powder, calcium silicate, magnesium silicate,aluminum silicate, sodium silicate, polyvinylpyrrolidone,polysaccharide, free flowing silica, mica, cellulose powder, kraftlignin, lignosulfonates, sulfosuccinates, sodium salt of polymerizednaphthalene sulfonic acid, sodium salt of carboxylated polyclectrolyte,POE stearates, dioleates, sodium butyl naphthalene sulfonates, sodiumsulfonate of naphthalene formaldehyde condensate, di-n-butyl sodiumnaphthalene sulfonate, di-isopropyl sodium naphthalene sulfonate, sodiumdodecylbenzene sulfonate, polyacrylates, polycarboxylates, solid blockco-polymers, POE lauryl alcohol and sorbitan stearates; and mixing saiddrying agent with said ammonium sulfate/drift reducing agent mixture.16. The method as claimed in claim 15, further comprising the steps of:adding to said ammonium sulfate/drift reducing agent mixture ananti-caking agent selected from the group consisting of silicon dioxide,tricalcium phosphate, silicas, fumed silicas, free flowing silicas,hydrophobic starch derivatives, powdered cellulose, calcium silicate,magnesium silicate, aluminum silicate, sodium silicate, polyacrylic acidand sodium salts thereof, and sodium polyalkyl naphthalene sulfonate;and mixing said anti-caking agent with said ammonium sulfate/driftreducing agent mixture and said drying agent to form adjuvant mixture.17. The product produced according to the method of claim
 16. 18. Themethod as claimed in claim 16, wherein said liquid drift reducing agentis liquid polyacrylamide.
 19. The method as claimed in claim 18, whereinsaid drying agent comprises between 0.01 and 20.0 weight percent of saidadjuvant mixture and said anti-caking agent comprises between 0.01 and0.0 weight percent of said adjuvant mixture.
 20. The product producedrecording to the method of claim 19.